The group arrived in Beirut from Syria on Thursday, and had been set to board two Turkish planes for Istanbul, a security source said.
But they "spent the night in the airport after the two Turkish planes failed to transport them" due to technical and logistical failures, said Mohammad Shahabeddine, the head of Lebanon's civil aviation service.
Overnight, a new regulation came into force requiring Syrians arriving in Turkey by air and sea to have visas, said a Turkish foreign ministry official.
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Previously, Syrians had been allowed to enter Turkey for visa-free stays of up to 90 days over a six-month period.
The new restriction that took effect overnight had been announced last month.
Shahabeddine said Lebanese airport authorities had scheduled extra flights prior to Friday in order to accommodate large groups of Syrians attempting to take advantage of the remaining days of visa-free entry.
But the group of nearly 400 missed the deadline, and were forced to return to Syria, Shahabeddine added.
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Fadi al Hassan, the head of Beirut international airport, said Syrian airline "Cham Wings is now returning 370 Syrian passengers to Damascus".
"A plane has already transported the first group, and we are waiting two more groups," Hassan said.
The announcement of the Turkish visa requirement sparked a reciprocal move from Damascus, which said on December 17 that Turks entering Syria would need visas.
The tit-for-tat new regulations come after six years of visa-free travel for citizens of both countries.
Once an ally of Damascus, Ankara cut diplomatic ties with President Bashar al Assad after the beginning of Syria's uprising in March 2011.
Turkey has become a leading backer of the opposition to Assad, and Syria accuses it of supporting "terrorist" groups.
Turkey and Lebanon host the highest numbers of Syrian refugees, with 2.2 million living in Turkish territories and just over one million in Lebanon.
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